1. Field
The disclosure relates to a method, system, and computer program product for an output driven generation of a combined schema from a plurality of input data schemas.
2. Background
An Extract, Transform and Load (ETL) job may be executed as a process in a database management system. During execution of the ETL job, data may be extracted from input data provided by input sources and transformed to fit operational needs. The transformed data may be loaded into a target, such as a database.
A schema refers to the structure of data described in a notation that is supported by a database management system. For example, a schema may indicate the organization of a table used to represent data. In certain situations, an input schema (also referred to as an input data schema) that describes the input data may be provided to an ETL job processor that process ETL jobs in a database management system. The input data is interpreted in accordance with the input schema to generate transformed data that is loaded into a target, where the transformed data may be referred to as an output.
ETL job processors that process ETL jobs may be driven by the input data received from input sources. In many situations, a single input schema that is fixed may be used by an ETL job processor to process the input data that is received from the input sources. In other situations, multiple input schema versions may be provided. In such situations, in order to parse the input data, a graphical user interface may be used to design one ETL job for each input schema version. That is, at job design time a user may be provided with schemas that describe input data and the user may select from among the schemas for each ETL component for a job, so that at runtime the ETL job processes input data based on the schemas that were provided to and selected by the user for the job design prior to runtime.